Apparatus for stopping mechanically driven presses



Feb. 28, 1967 A. WEBER 3,306,413

APPARATUS FOR STOPPING MECHANICALLY DRIVEN PRESSES Filed Se t. 6, 1966 4 Sheets-Sheet l Feb. 28, 1967 A. WEBER 3,306,413

APPARATUS FOR STOPPING MECHANICALLY DRIVEN PRESSES Filed Sept. 6, 1966 4 Sheets-Sheet 2 A. WEBER 3,306,413

APPARATUS FOR STOPPING MECHANIGALLY DRIVEN PRESSES Feb. 28, 1967 4 Sheets-Sheet 3 Filed Sept. 6, 1966 FIG, 3

INVENTOR. ALFRED WEBER A. WEBER Feb. 28,1967 3,306,413

APPARATUS FOR STOPPING MEGHANICALLY DRIVEN PRESSES v 4 Sheets-Sheet 4 Filed Sept. 6, 1966 FIG.

F IG. 6

Fl 6 I 9 FIG. 8

INVENTOR. ALFRED WEBER ATTORNEYS United States Patent 3,306,413 APPARATUS FOR STOPPING MECHANICALLY DRIVEN PRESSES Alfred Weber, Hammerstrasse 43, Bad Berneck, Bavaria, Germany Filed Sept. 6, 1966, Ser. No. 584,295 Claims priority, application Germany, Aug. 28, 1963, W 35,177 3 Claims. (Cl. 192-144) This application is a continuation-in-part of my copending application Ser. No. 392,432, filed Aug. 27, 1964, now abandoned.

This invention relates to an apparatus for stopping mechanically driven presses, by means of a brake, employing a rotary key coupling with an arrester ring the cams of which co-operate with a displaceable member.

The problem of stopping presses is of a very great importance, owing to the high accident rate on these machines. The masses to be moved are considerable, and so special measures are required for arresting them. For this reason, the engaging members of the rotary key coupling are so dimensioned as to have great strength, in order to meet effectively the danger of fracture, but nevertheless, the arrester rings do break, possibly together with the r0- tary key, so that the press races.

On the other hand, it is also known that an accidental interruption of the stroke of a press, when the punch below the ram has already penetrated into the material, may lead to a breaking of the coupling members. This is because the rotary key, owing to excessive surface pressure during the stamping or withdrawing process, is not released from its bush and so the flywheel mass, i.e. the flywheel or the cogwheel, cannot be separated from the eccentric shaft.

Brakes acting on the eccentric shaft of a press have already been proposed; these may be electrically controlled by scanning or sensor contacts and are intended to arrest the press in case of accident. been proposed which are intended to effect cushioned disengagement of the rotary key coupling, so that fracture of the rotary key or of other machine parts is avoided. However, these proposed devices do not take into account the fact that the flywheel or cogwheel which continues to rotate constitutes a great source of danger.

It is an object of the present invention to provide a device which reduces or eliminates the above shortcomings of known presses and immediately stops the press in case of danger.

According to the present invention there is provided an apparatus for stopping mechanically driven presses by mean-s of a brake, comprising a rotary key coupling and an arrester ring having cams or the like which co-operate with a displaceable member, wherein a brake is arranged adjacent the flywheel of the press and the displaceable member is mounted for displacement by a cam or the like of the arrester ring and is mechanically coupled with a switch arranged to cut off the press drive and with means for actuating the brake.

This arrangement offers the advantage over the previously known presses that in case of danger not only the press is switched off, but the flywheel of the press is also stopped. This is effected by the displaceable member which is coupled with the brake-actuating mechanism. The arrangement also provides an improved safety factor in that the displaceable member simultaneously actuates a cut-off switch of the press drive.

Braking device have In an embodiment of the invention, the displaceable member is resiliently mounted in a guide of a pivotal control lever, and has a wedge-shaped ramp face co-operating with a stationary stop.

The displaceable member acquires in this manner its axial component of movement for actuating the brake and for switching off the press drive, thereby preventing fracture and all its detrimental consequences.

According to another feature of the invention, the displaceable member carries a projection in the range of movement of which the cut-off switch is located.

It is further within the scope of the invention to provide a mechanical coupling between the displaceable member and the brake comprising a rod linkage bearing against the member in force-transmitting contact under the loading of a spring and co-operating with a locking lever for the brake.

While this locking lever is effective, the brake is disengaged. If, however, the locking lever is released by actuating the displaceable member and the' intervening rod linkage, the brake is freed and instantaneously engages and stops the flywheel.

According to the invention, the brake block is mounted obliquely and, in the disengaged position, bears with one face against the load arm of a bell-crank lever, the forcearm of which co-operates with the locking lever of the brake lever arrangement. This force-arm is advantageously loaded with a weight which actuates tightening of the brake when the bell-crank lever is released by the locking lever.

According to the invention, the mechanical coupling between the displaceable member and the cut-off switch has a smaller play than that between the member and the brake. The result hereof is that, in case of danger, the motor of the press is switched off first, followed by the engagement of the brake at a very brief time interval.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a partly exploded side elevation of a press of which a few parts are omitted;

FIG. 2 is a fragmentary view in the direction of arrow H of FIG. 1;

FIG. 3 is a view partially in section through the rotary key coupling;

FIG. 4 is a section on the lines 4-4 of FIG. 3 showing the coupling in its released position;

FIG. 5 is a section on the same lines as FIG. 4, but showing the coupling in its engaged condition;

FIG. 6 is a section on the lines 66 of FIG. 3 showing the coupling in its released condition;

FIG. 7 is a section on the same lines as FIG. 6 showing the coupling in its engaged position;

FIG. 8 is a section on the lines 8-8 of FIG. 3 showing a coupling in released position; and

FIG. 9 is a section on the same lines as FIG. 8 showing the coupling in engaged position.

In machine frame 1 which is not relevant to the invention is only generally indicated, there is mounted shaft 2 on which flywheel 3 is mounted. Coupling between the shaft and the flywheel is effected by a rotary key 4 which engages partly in a groove of the drive shaft 2 and partly in a recess 5' of an arrester ring 6 mounted on the shaft 2. The direction of rotation of the flywheel 3 is indicated by the arrow 7.

Referring now to FIGS. 3 to 9 inclusive for a description of the rotary key coupling between the flywheel and the shaft and the manner of operation of this coupling by the arrester ring, the shaft 2 is coupled and de-coupled to the flywheel 3 by means of a rotary coupling member 4. The relationship between these parts is shown most clearly in FIGS. 3, 8 and 9. The rotary key coupling is always engaged with the arrester ring 6 and this relationship is shown most clearly in FIGS. 3, 4 and 5. The arrester ring 6 carries a pair of cams or abutment members 8 and 9. Whenever the rotation of the arrester ring 6 is interfered with, as for example by means of an abutment member placed in the path of rotation of the cams, the effect is to de-couple the flywheel 3 from the shaft 2. This position of the parts is shown in FIGS. 4 and 8 in which the arresting ring 6 is held by the movable abutment 10.

As shown in FIGS. 6 and 7, which are both sectional views on the lines 6-6 of FIG. 3, a biasing spring member 60 is shown, which normally biases the rotary coupling member 4 toward coupling position as shown in FIG. 5. If the shaft 2 is rotated backward, the arresting ring 6 can be moved to flywheel coupling position as shown in FIGS. 5, 7 and 9. The rotary coupling key 4 is thus rotated on its own axis.

In normal operation of the press, the rotary key coupling is in the position where the flywheel 3 is coupled to the shaft 2 and following one revolution of the press, the abutment 10 is placed into the path of the cams 8 and 9 which is effective to de-couple the flywheel from the shaft at the end of the press stroke. The present invention is concerned with preventing dam-age to the press in the event that for some reason at the end of a press cycle, the rotary key coupling jams or breaks in some manner which prevents de-coupling of the flywheel from the shaft.

The arrester ring 6 carries two cams 8 and 9. Into the range of movement of these cams 8, 9, projects lug 10 of a displaceable stopping member 11, which is mounted on arm 12 of a control lever 14 pivotable about pin 13. To this end, the free end of the lever arm 12 is fork-shaped and the two branches 15 of the fork are connected by a bolt 16. In guide 17 constituted by the fork branches 15 and the bolt 16 of the lever arm 12, the displaceable member is maintained by a stem 18 in the position, shown in FIG. 1, bearing against the bolt 16. The stem 18 is located in a recess 19 of the lever arm 12 and is under the action of cup springs 20.

On its underside, the lug 10 of the member 11 has a ramp face 21, which co-operates with a stationary stop 22 when the lug 10 is acted on by one of the cams 8 or 9 of the arrester ring 6. Owing to the face 21 sliding on the stop 22, the member 11 executes a movement into the position 23 indicated by broken lines.

References 24 and 25 designate an engaging rod linkage to be actuated in a known manner; the lever 25 pivots about hinge point 26 and during a movement in the direction of arrow 27 raises setting lever 28, so that the control lever 14 is pivoted about its center of rotation 13 to the position indicated by broken lines, thus moving the lug 10 out of engagement with cam 8 or 9. In this state, the press is operative. During this sequence of movements, the member 11 pivots together with the arm 12 of the control lever 14, without being axially displaced in relation to its guide 17.

On a support 29 secured to the machine frame 1, there is arranged a slide 30 arranged obliquely. On this slide rests a brake block 31, which is intended to engage peripheral surface 32 of the flywheel 3. FIG. 1 shows the position with the brake block 31 retracted. End 33 of the brake block 31 bears against a compression spring 34, which in turn has a counter-bearing 35. Compression screw 36 serves for releasing the brake block 31 from the flywheel 32 in case the force of the spring 34 should not be suflicient to effect this.

Face 37 of the brake block 31 is formed as a wedge surface. Against this bears roller 38 of load arm 39 of a bell-crank lever 41 which is pivotable about axis 40. The force arm 42 of lever 41 is under the loading of a weight 43 and is extended at one end to a grip 44. This force arm 42 is within the range of movement of a locking lever 45, which is mounted on shaft 46. The shaft 46 is mounted in the machine frame 1, in bearings 47 and 48, and carries on its other end a trip lever 49 on which rod 50 rests. Rod 50 is guided in bearing 51 in the machine frame 1, and has two adjusting rings 52 and 53 which define the range of its axial movement. A compression spring 54 is provided between the adjusting ring 53 and the bearing 51.

The locking lever is associated with a safety bolt 55. In turn, the member 11 has a projection 56 in the range of movement of which there is located operating lever 57 of cut-otf switch 58 of the press drive motor (not shown).

When the press is to be stopped, the member 11 with its lug 10 is brought within the range of movement of the rotating cams 8, 9 of the arrester ring 6 (see FIG. 1) by actuating the engaging rod engagement 24, 25, 28. As soon as one of the cams 8, 9 meets the lug 10, the latter is pivoted downward against the section of the springs 20, so that the face 21 engages and runs on the stationary stop 22. Thus, the control lever 14 pivots about its pin 13. During this movement, end 59 of the member 11 first runs the distance a whereby the projection 56 actuates the lever 57 and the cut-off switch 58, so that the drive motor of the press is stopped. In the further course of the movement of the member 11 initiated by the action of one of the cams 8, 9, the end 59 covers the distance b whereby the rod linkage is moved against the action of the spring 54 in the direction of arrow 60 and acts on the trip lever 49, so that the shaft 46 and with this the locking lever 45 are pivoted. Lug 61 of the locking lever 45 frees the force arm 42 of the bell-crank lever 41. Under the action of the weight 43, the lever 41 pivots about its axis 40 and the load arm 39 bears with the roller 38 against the wedge face 37 and displaces the brake block 31 in the direction of arrow 62 for engagement with the external circumference 32 of the flywheel 3 which is thereby arrested instantaneously.

For disengaging the brake, the arm 42 of the lever 41 is raised by means of the grip 44, so that the compression spring 34 can move the brake block 31 in the direction opposite to that of arrow 62. If the force of the spring is insuflicient to effect this, then the disengaging screw 36 can be actuated. When the lever arm 42 is raised, the lug 61 of the locking lever 45 is again engaged, so that the situation shown in FIGS. 1 and 2 is re-established.

Applicant claims the benefit of a full range of equivalents within the scope of the appended claims.

I claim:

1. A rotary drive press comprising in combination:

a shaft;

a flywheel mounted for rotation with said shaft;

means comprising a releasable rotary coupling joining said flywheel to said shaft;

means for releasing said rotary coupling to de-couple said flywheel from said shaft after each cycle of the press;

a brake shoe positioned adjacent to said flywheel for engagement therewith;

means for forcing said brake shoe into engagement with said flywheel; and

means carried by said shaft for actuating said lastmentioned means whenever said rotary coupling fails to de-couple said flywheel from said shaft following each cycle of the press.

2. A press as defined by claim 1 and further including 5 a switch for cutting ofl? the supply of power to the press, said switch being operable by said last-mentioned means. 3. A press as defined by claim 1 in which the means for releasing said rotary coupling comprise an arrester ring mounted for rotation with said shaft, said ring in- 5 eluding cam means on its outer periphery; and movable abutment means positioned to be engaged by said cam means following each cycle of the press.

References Cited by the Examiner UNITED STATES PATENTS 1,681,646 8/ 1928 Papas 192144 X 1,706,141 3/1929 Byerlein 192144 3,084,777 4/ 1963 McCallum et al. 192-144 DAVID J. WILLIAMOWSKY, Primary Examiner. A. T. MCKEON, Assistant Examiner. 

1. A ROTARY DRIVE PRESS COMPRISING IN COMBINATION: A SHAFT; A FLYWHEEL MOUNTED FOR ROTATION WITH SAID SHAFT; MEANS COMPRISING A RELEASABLE ROTARY COUPLING JOINING SAID FLYWHEEL TO SAID SHAFT; MEANS FOR RELEASING SAID ROTARY COUPLING TO DE-COUPLE SAID FLYWHEEL FROM SAID SHAFT AFTER EACH CYCLE OF THE PRESS; A BRAKE SHOE POSITIONED ADJACENT TO SAID FLYWHEEL FOR ENGAGEMENT THEREWITH; MEANS FOR FORCING SAID BRAKE SHOE INTO ENGAGEMENT WITH SAID FLYWHEEL; AND MEANS CARRIED BY SAID SHAFT FOR ACTUATING SAID LASTMENTIONED MEANS WHENEVER SAID ROTARY COUPLING FAILS TO DE-COUPLE SAID FLYWHEEL FROM SAID SHAFT FOLLOWING EACH CYCLE OF THE PRESS. 